Author Topic: 1N34A diodes. Cheap vs expensive.  (Read 2350 times)

mozz

Re: 1N34A diodes. Cheap vs expensive.
« Reply #40 on: February 13, 2021, 04:43:46 PM »
Original picture i can see the corrosion on the leads, usually old stock does that. I have hundreds of old germanium diodes and also hundreds of old silicon, all from the 50-60's from my dads tv shop. I don't think i have a schottky here to compare. I'm going to pull out my old Hickok germanium transistor tester. It measures a lot of parameters for transistors and i know there is a section in the book on diodes, will have to see what i can measure. There are usually color coded bands but i have seen many japanese diodes i scrapped from radios that i know are germanium but are clear glass.
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Rob Strand

Re: 1N34A diodes. Cheap vs expensive.
« Reply #41 on: February 13, 2021, 11:46:18 PM »
The bottom of this page has some measurements of  the diode "slope" parameter "n".   The results are done at very low currents.

https://www.lessmiths.com/~kjsmith/crystal/dpiii.shtml

You can see the n for Schottky's tends to have n < 1.2 and germaniums have n > 1.2.  If you test at higher currents you should see a similar pattern.  "n" affects the softness of the clipping.

There's also this type of diode (the geranium diode) which tends to flourish this time of year.  The only diode that doesn't smell bad when the smoke gets out.

The internet:  answers without the need for understanding.

bluebunny

Re: 1N34A diodes. Cheap vs expensive.
« Reply #42 on: February 14, 2021, 04:08:40 AM »
"What did you get for your Valentines gift?"

"A diode."   :icon_confused:
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Ohm's Law - much like Coles Law, but with less cabbage...

anotherjim

Re: 1N34A diodes. Cheap vs expensive.
« Reply #43 on: February 14, 2021, 05:18:23 AM »
Ok, but testing when you get them is a little late in the game. It would help to know how to judge the listing.

We know that some suppliers consider Schottky to be equivalent/replacement for obsolete germanium.  If you search for a germanium part, it could well offer Schottky in this belief.
We also know that you can't trust the photo of the offering to be correct. Very often it's any picture of any diode that was handy.
We probably do know what the price of the offering is. If it's at mass-produced silicon prices, then that's probably what it is.
Croeso i Diystompboxes.

If they didn't hear you then you didn't say it.

mark2

Re: 1N34A diodes. Cheap vs expensive.
« Reply #44 on: February 14, 2021, 04:06:52 PM »
Anyone using the ones NTE sells, either direct or through digikey? ~$0.70/each. Seem to be new

I got some recently and their Vf is fine, but I haven't done any further checking or testing.

I'm wondering if they're schottky.




rankot

Re: 1N34A diodes. Cheap vs expensive.
« Reply #45 on: February 14, 2021, 05:08:05 PM »
Anyone using the ones NTE sells, either direct or through digikey? ~$0.70/each. Seem to be new

I got some recently and their Vf is fine, but I haven't done any further checking or testing.

I'm wondering if they're schottky.




Those seem to be Ge.
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50 pedals and counting!

iainpunk

Re: 1N34A diodes. Cheap vs expensive.
« Reply #46 on: February 14, 2021, 07:43:38 PM »
we can discuss whether or not diodes are true Ge or if they are fake/schottky... but i wonder 'if' and/or 'how much' it actually matters.
in a clipping situation, i couldn't tell you in a blind test if they are Ge or schottky, i used to be convinced i could, but after doing blind testing, i can't.
some germaniums sounded harsher and some softer, while the schottky diodes were generally more middle of the road, but they too had types that are softer or harder.
i don't want to stirr up a heated debate like those you can find on gear forums, but i like to hear other peoples experiences and opinions.

cheers, Iain
half man - half snail - 6 feet to scale - Snail man's - not frail - He's been - to jail - snail man is fuccing real
『snailpilled』

PRR

Re: 1N34A diodes. Cheap vs expensive.
« Reply #47 on: February 14, 2021, 09:06:21 PM »
Anyone using the ones NTE sells, either direct or through digikey? ~$0.70/each. Seem to be new....

NTE has been doing business for 42 years. Their stuff has very long shelf life; until last year I could go into Greenbrook Electronics and find ECG/NTE parts from the last century. I don't know that old diodes are surely fresher from DigiKey or NTE itself.
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PietS

Re: 1N34A diodes. Cheap vs expensive.
« Reply #48 on: March 07, 2021, 05:36:19 PM »
I finally got my orders from China in and did some measurements. I made a simple test rig with a 9V battery, a 10k pot + 40 ohm resistor as a voltage divider. It's not good to test higher currents but I was mainly interested in the slope and smoothness of I-V curve at lower values anyway.

The moderately priced 1N34A mentioned before are called 1N34A-M in the figure. I tested 3 of those but the values were very similar so I just averaged them.
I got 2 expensive 1N34A, that had the cat whisker and all, in the figure they are called -E1 and -E2.
I also got a some cheap "1N34A" that were not see-through but orange (-C). I bought them together with some "germanium" 1N60 that had similar packaging except for some small print on the glass. The V-I curve of all these diodes were the same, so probably all the same diodes but a few with the print rubbed off. I also tested a few BAT41's and silicone 1N4148's for reference.

The moderately priced 1N34A and the cheap 1N34A and 1N60 are probably all Schottky diodes as their V-I curves are at low voltages and steep. The expensive 1N34A's had a different curve as the others, but the slope was very flat and the red one (-E1) really had lower current at the highest voltage. At 600mV the conduct similar amounts as a silicone diode which seems wrong. They are probably real 1N34A but just not very good ones   >:(




« Last Edit: March 07, 2021, 05:39:38 PM by PietS »

iainpunk

Re: 1N34A diodes. Cheap vs expensive.
« Reply #49 on: March 07, 2021, 06:58:18 PM »
i want to get my hands on diodes which have that red curve, might give some cool semi-wave-folding grind especially if the curve goes down further at that rate.

to bad you got some bad / semi-fake diodes, but the real question is; which sound better to you?
or do they just have different characters which are good for different types of distortion? even better yet, how do they sound together in asymmetric clipping???

cheers
half man - half snail - 6 feet to scale - Snail man's - not frail - He's been - to jail - snail man is fuccing real
『snailpilled』

Rob Strand

Re: 1N34A diodes. Cheap vs expensive.
« Reply #50 on: March 07, 2021, 07:47:39 PM »
Quote
The moderately priced 1N34A mentioned before are called 1N34A-M in the figure. I tested 3 of those but the values were very similar so I just averaged them.
I got 2 expensive 1N34A, that had the cat whisker and all, in the figure they are called -E1 and -E2.
I also got a some cheap "1N34A" that were not see-through but orange (-C). I bought them together with some "germanium" 1N60 that had similar packaging except for some small print on the glass. The V-I curve of all these diodes were the same, so probably all the same diodes but a few with the print rubbed off. I also tested a few BAT41's and silicone 1N4148's for reference.
The orange package ones are likely to be Schottkys.    I've got a lot real germaniums which sit around the same voltages as the Schottky until you get to 1mA where it starts to deviate and by 10mA the difference between the germaniums and Schottkys is clear.

The -E1 and -E2 curves look very different.  Perhaps more different to what I generally see.   I'd have to pull out some very old stuff to see if any were like those.   Unfortunately I thew out most of my old original Ge's a *long* time ago.

FWIW, your 1N4148 curve looks a bit different to what I'm used to.

The BAT41's looks a bit high as well.
Data sheet is 260mV @ 100uA and 360mV @ 1mA.
My BAT46's were 200mV @ 100uA and 270mV @ 1mA.
You curve is 260mV @ 100uA but is aiming at 540mV @ 1mA;  looks like quite a bit more series resistance, like 180 ohms!

« Last Edit: March 07, 2021, 09:24:06 PM by Rob Strand »
The internet:  answers without the need for understanding.

Gus

Re: 1N34A diodes. Cheap vs expensive.
« Reply #51 on: March 07, 2021, 08:03:42 PM »
Anyone using the ones NTE sells, either direct or through digikey? ~$0.70/each. Seem to be new....

NTE has been doing business for 42 years. Their stuff has very long shelf life; until last year I could go into Greenbrook Electronics and find ECG/NTE parts from the last century. I don't know that old diodes are surely fresher from DigiKey or NTE itself.

Don't forget Masters

PietS

Re: 1N34A diodes. Cheap vs expensive.
« Reply #52 on: March 08, 2021, 09:52:57 AM »
i want to get my hands on diodes which have that red curve, might give some cool semi-wave-folding grind especially if the curve goes down further at that rate.

to bad you got some bad / semi-fake diodes, but the real question is; which sound better to you?
or do they just have different characters which are good for different types of distortion? even better yet, how do they sound together in asymmetric clipping???

cheers

True, the real question is how they sound. I'll just try them all and see what I like best.

PietS

Re: 1N34A diodes. Cheap vs expensive.
« Reply #53 on: March 08, 2021, 10:09:11 AM »
Quote
The moderately priced 1N34A mentioned before are called 1N34A-M in the figure. I tested 3 of those but the values were very similar so I just averaged them.
I got 2 expensive 1N34A, that had the cat whisker and all, in the figure they are called -E1 and -E2.
I also got a some cheap "1N34A" that were not see-through but orange (-C). I bought them together with some "germanium" 1N60 that had similar packaging except for some small print on the glass. The V-I curve of all these diodes were the same, so probably all the same diodes but a few with the print rubbed off. I also tested a few BAT41's and silicone 1N4148's for reference.
The orange package ones are likely to be Schottkys.    I've got a lot real germaniums which sit around the same voltages as the Schottky until you get to 1mA where it starts to deviate and by 10mA the difference between the germaniums and Schottkys is clear.

The -E1 and -E2 curves look very different.  Perhaps more different to what I generally see.   I'd have to pull out some very old stuff to see if any were like those.   Unfortunately I thew out most of my old original Ge's a *long* time ago.

FWIW, your 1N4148 curve looks a bit different to what I'm used to.

The BAT41's looks a bit high as well.
Data sheet is 260mV @ 100uA and 360mV @ 1mA.
My BAT46's were 200mV @ 100uA and 270mV @ 1mA.
You curve is 260mV @ 100uA but is aiming at 540mV @ 1mA;  looks like quite a bit more series resistance, like 180 ohms!

It was pretty quick and dirty and I'm sure my simple test rig gets unreliable with higher currents. Up to 200-300 uA it's probably ok, but I wouldn't trust the accuracy above it. The point of adding the BAT41 and 1N4148 was to have something to compare to but more in a relative way than in an absolute way.